A cystotomy is a surgical procedure which cuts or forms a surgical pathway between the bladder and the exterior abdomen through the intervening abdominal tissue. A cystotomy establishes access to the interior of the bladder. A cannula is inserted into the surgical pathway to create an access pathway for inserting medical instruments into the bladder. A variety of different medical procedures can be performed inside the bladder using the instruments inserted through the cannula.
A cystostomy is a surgical procedure which cuts or forms a surgical pathway between the bladder and the exterior abdomen through the intervening abdominal tissue for the purpose of establishing an additional urine drainage pathway from the bladder, such as when the urine flow path through the natural urinary canal is inhibited or obstructed. Once the surgical pathway has been formed, a hollow tubular urine drainage catheter is inserted in the surgical pathway. Urine is drained from the bladder through the catheter. The catheter initially remains in place long enough for the surrounding tissue to form a tract or sinus between the bladder and the exterior abdomen. Thereafter, the catheter is replaced periodically in order to help prevent infection. A cystostomy is typically required when urine flow is blocked by swelling of the prostate (benign prostatic hypertrophy), traumatic disruption of the urethra, congenital defects of the urinary tract, obstructions such as kidney stones passed into the urethra, or cancer. A cystostomy is also a common treatment used among spinal cord injury patients who are unable or unwilling to use intermittent catheterization to empty the bladder and cannot otherwise void due to detrusor sphincter dyssynergia.
In both a cystotomy and a cystostomy, a surgical pathway is created between the bladder and the exterior abdomen through the intervening abdominal tissue. Because of the common aspects of forming the surgical pathway, the term “cystotomy,” as used herein, will refer to forming the surgical pathway between the bladder and the exterior abdomen through the intervening abdominal tissue, regardless of whether a catheter is inserted in the surgical pathway as an auxiliary urine drainage passageway or a cannula is inserted in the surgical pathway to receive and accept surgical instruments for performing a medical procedure within the bladder.
There are two general techniques for performing a cystotomy. An “outside-in” cystotomy, sometimes referred to as a percutaneous cystostomy, is performed by cutting the surgical pathway from the exterior abdomen through the intervening abdominal tissue into the bladder. An “inside-out” cystotomy is sometimes referred to as a transurethral cystotomy because access to the interior of the bladder is achieved through the urinary canal. An inside-out a cystostomy is performed by cutting the surgical pathway from the bladder through the intervening abdominal tissue to the exterior abdomen.
An outside-in cystotomy typically involves the insertion of a needle from the exterior abdomen to inside the bladder. The insertion of the needle through the abdomen creates a surgical pathway into the bladder. A sheath surrounding the needle is kept within the surgical pathway when the needle is removed. Outside-in cystotomies are suitable for draining urine from the bladder, but are not typically suitable for performing medical procedures within the bladder because the small diameter size of the sheath is insufficient to accommodate medical instruments. One difficulty or disadvantage associated with outside-in cystostomies is the potential to puncture through the posterior wall of the bladder creating fistulas.
An inside-out cystotomy involves the use of a medical instrument called a sound. The sound is inserted through the urinary tract and is pushed against the bladder. The surgical pathway is then formed by forcing the sound from the bladder through the intervening tissue to the external abdomen. An inside-out cystotomy is generally considered a blind procedure because the surgeon lacks a precise visual indication of the location of the end of the sound within the bladder, unless a bulge on the abdomen can be created. It is typically impossible to tent or bulge the exterior abdomen of obese patients, because of the excess abdominal tissue. Instead, the surgeon generally must rely on personal skill and experience to position the sound and predict the location where the cutting blade will emerge.
All cystotomies carry some risk of complication. Potential complications from performing a cystotomy involve accidentally cutting the intestine. The intestines are located very close to the location where the surgical pathway is normally established. Furthermore, different patients have slightly different anatomies which makes it difficult to predict exactly the location of the intestines in the intervening tissue between the bladder and the external abdomen, particularly in the case of obese patients. Generally, imaging is not used during the procedure. The dangers from infection due to even a small and unintentional cut of the intestine are substantial, and a not-insignificant number of such incidents can result in death. Nevertheless, a cystotomy may be the only option for use with some patients who have greater risks of other medical problems resulting from not performing the cystotomy, or a cystotomy may be required or desirable as part of another surgical procedure.
To minimize the possibility of inadvertently cutting the intestine and to otherwise reduce tissue trauma, and because the sound must have a size capable of being inserted through the urinary tract, the cutting tip used to create the surgical pathway is relatively small in size. The small size helps to reduce the possibility of cutting adjacent tissues, such as the intestines. If a cannula is to be inserted within the surgical pathway, the surgical pathway must be expanded to accept the larger cannula. It is desirable to expand the size of the initial surgical pathway without unduely tearing the tissue and without inducing more trauma. It is also desirable to facilitate the use of medical equipment to perform the cystotomy, thereby reducing the time duration of the medical procedure and the trauma to the patient.
Additionally, known instruments currently available for use in cystotomies have no capability for effectively securing the bladder wall during the procedure, allowing for the possibility that the flaccid wall of the bladder may impede the procedure.